F(y) { 0 for y<0 ; y^2/50 for 0 =< y < 5 ; (2y/5) - y^2/50 for 5=<y=<10 ; 1 for y => 10}
this cdf is weird because if i plug 10 in, like (2(10)/5) - (10)^2/50) i got 2 instead of 1 . I don't understand, would someone like to explain to me thank you very much ^^

And, for y>10, you better get 1, which I did, since this is a valid denisty.
That was the first thing I did, to see if it integrated to one.
Too often students write down incorrect 'densities' and I spend forever on the problem.